The present invention relates to air distribution systems, in particular in the passenger compartment of a vehicle, e.g. of a motor vehicle, of the type comprising at least one opening or outlet for the outflow of air into the passenger compartment, one conduit for feeding a flow of air to said outlet, and means for activating the air outlet, i.e. for commanding the opening of the outlet and/or for enabling the feeding of the aforesaid flow of air to the outlet through said conduit.